Running cuts visceral fat, and you can run through pain

Some pretty remarkable data was recently presented at the Radiological Society of North America conference in Chicago. German researchers followed a group of 44 runners during the 4,488-kilometre TransEurope Footrace from southern Italy to northern Norway in 2009, carting along a 45-ton mobile MRI unit and a host of other diagnostic equipment:

Urine and blood samples as well as biometric data were collected daily. The runners were also randomly assigned to other exams, including electrocardiograms, during the course of the study. Twenty-two of the runners in the study underwent a whole-body MRI exam approximately every three or four days during the race, totaling 15 to 17 exams over a period of 64 days. At the close of the race, researchers began to evaluate the data to determine, among other things, stress-induced changes in the legs and feet from running. Whole-body volume, body fat, visceral fat, abdominal subcutaneous adipose tissue (SCAT), and fat and skeletal muscle of the lower extremities were measured. Advanced MRI techniques allowed the researchers to quantify muscle tissue, fat and cartilage changes.

So what did they learn from all this (other than, presumably, that anyone who enters a 4,488-kilometre is pretty fit and pretty crazy)? They highlight a few key points:

The runners lost a lot of fat — half of their starting amount. And most of that was lost during the first 2,000 km. (Oh, it only takes 2,000 km? How easy!) Even better, the first fat to start disappearing was the visceral fat, which surrounds the internal organs and is the really bad stuff that’s linked to heart disease. The runners lost 70 percent of their visceral fat.

It’s possible to run through some soft-tissue injuries without doing long-term damage. Other problems, like joint issues and stress-fractures, require rest. The press release includes this quote: “The rule that ‘if there is pain, you should stop running’ is not always correct,” Dr. Schütz said. However, they don’t give much guidance on which injuries you can run through. Presumably you need a mobile MRI unit to tell you for sure.

The runners also lost 7 percent of the muscle in their legs, which they call “one of the most surprising things,” but doesn’t really seem that shocking. Running that much in two months is well outside the bounds of even extreme marathon training. If I’m understanding correctly, they did about eight weeks of 550 km a week!

Anyway, this was just a conference presentation at this point. It’ll be interesting to see the full data when it’s eventually published… but it’s probably not something you should emulate.